Interoperable aerial refueling apparatus and methods

ABSTRACT

Interoperable aerial refueling apparatus and methods are disclosed. In one embodiment, a receptacle configured to fluidly receive a terminal portion of a refueling boom is coupled to a refueling drogue. A retainer is coupled to an aircraft that removably retains the receptacle when the aircraft is refueling another aircraft configured to directly engage the boom. The receptacle releases the receptacle when the terminal portion of the boom engages the receptacle so that an aircraft that receives the refueling drogue may be refueled. In another embodiment, a method includes providing fuel to a first receiving aircraft that receives fuel by directly coupling to an end of a refueling boom. The method further includes, while the tanker aircraft is in flight, configuring the boom to supply fuel to a second receiving aircraft having a refueling probe operable to receive fuel from a drogue.

FIELD OF THE INVENTION

The present invention relates generally to apparatus and methods foraerial refueling of aircraft, and in particular to interoperable aerialrefueling apparatus and methods.

BACKGROUND OF THE INVENTION

Aerial refueling, or “in-flight” refueling, has long been used toincrease the endurance of an aircraft. In general terms, a fuel supplycarried within a supply aircraft, commonly known as a “tanker,” istransferred to a receiving aircraft that typically follows the tankerand engages a fuel transfer device that is deployed from the tanker.Following the engagement, fuel is transferred from the tanker to thereceiving aircraft through the fuel transfer device. Following thetransfer of a desired amount of fuel, the receiving aircraft disengagesthe fuel transfer device and departs.

In one commonly used aerial refueling system, known as the “probe anddrogue” system, a retractable hose is deployed from the tanker thatincludes a drogue or “basket” coupled to a trailing end of the hose. Thedrogue further includes a valve positioned on an inner portion of thedrogue that interrupts a flow of fuel to the receiving aircraft when theaircraft disengages the drogue. The receiving aircraft includes a probethat extends forwardly from the receiving aircraft that is configured toengage the valve positioned within the drogue, so that the receivingaircraft may receive fuel from the tanker.

In another commonly used aerial refueling system, known as the “boom andreceiver” system, the fuel transfer device comprises a boom that iscoupled to a rear portion of the tanker. The boom includes an elongated,rigid and hollow shaft operable to transfer the fuel, and a telescopingextension portion positioned at an end of the boom. The telescopingextension portion includes a valve configured to be received by acorresponding fuel receiver on the receiving aircraft. The boom alsoincludes a ruddervator assembly generally comprised of airfoils thatpermit the tanker to controllably maneuver the boom relative to thereceiving aircraft. Accordingly, during an aerial refueling operation,the tanker will release the boom from a stowed position and extend thetelescoping portion of the boom. The boom may then be directed towardsthe receiving aircraft by controlling the aerodynamic surfaces to guidethe end of the boom into the fuel receptacle on the receiving aircraft.While the boom and the receiver portion are coupled, the telescopingextension portion permits fuel to be continuously transferred byaccommodating small relative motions occurring between the tanker andthe receiving aircraft.

Although the foregoing aerial refueling systems achieve desirableresults, certain drawbacks exist. In particular, an incompatibilityexists between tanker aircraft that are configured with the boom andreceiver system and a receiving aircraft configured for the probe anddrogue system. In order to permit refueling operations between tankershaving a refueling boom and probe-equipped receiver aircraft, arefueling adapter, as shown in FIG. 1 may be employed. The refuelingadapter 10 includes a hose 12 having a drogue 14 positioned at one end,and a boom-mating portion 16 positioned on an opposing end. Theboom-mating portion 16 is configured to be removably coupled to thetelescoping extension portion 18 of the boom 20, so that fuel within thetanker (not shown in FIG. 1) may be transferred to the drogue 14. Duringan aerial refueling operation employing the refueling adapter 10, theboom 20 is released from the stowed position, and controllablymaneuvered towards the receiving aircraft (also not shown in FIG. 1).Although FIG. 1 shows the refueling adapter 10 in a non-flightcondition, with the hose 12 and the drogue 14 depending downwardly fromthe boom 20, it is nevertheless understood that while the tanker is inflight, the hose 12 and the drogue 14 extend generally outwardly andbehind the boom 20 due to aerodynamic drag. When the boom 20 having therefueling adapter 10 is properly positioned, the probe of the receivingaircraft engages the drogue and receives fuel.

One drawback associated with the foregoing refueling adapter 10 is thatit must be installed on the boom 20 prior to flight, and cannot beremoved while the tanker is in flight. Consequently, once the boom 20 isconfigured with the refueling adapter 10, the tanker cannot refuelaircraft configured for the boom and receptacle equipped receiversystem.

What is needed in the art is an improved aerial refueling system that isinteroperable, so that a tanker configured for the boom and receptaclesystem may also be configured to refuel aircraft configured with theprobe and drogue system without employing a ground-mounted adaptor.

SUMMARY OF THE INVENTION

The present invention comprises interoperable aerial refueling apparatusand methods. In one aspect of the invention, an apparatus includes areceptacle fluidly coupled to a refueling drogue, the receptacle beingconfigured to fluidly receive a terminal portion of a refueling boomcoupled to a tanker aircraft while in flight. The apparatus furtherincludes a retainer coupled to the tanker aircraft that removablyretains the receptacle when the tanker aircraft is refueling an aircraftconfigured to directly engage the terminal portion of the boom, and thatreleases the receptacle when the terminal portion of the refueling boomengages the receptacle, so that an aircraft configured to receive therefueling drogue may be refueled.

In another aspect, a method includes providing fuel to a first receivingaircraft configured to receive fuel by directly coupling to a terminalend of a refueling boom coupled to a tanker aircraft. The method furtherincludes, while the tanker aircraft is in flight, configuring the boomof the tanker aircraft to supply fuel to a second receiving aircrafthaving a refueling probe operable to receive fuel from a refuelingdrogue.

BRIEF DESCRIPTION OF THE DRAWINGS

The preferred and alternative embodiments of the present invention aredescribed in detail below with reference to the following drawings:

FIG. 1 is an isometric view of an aerial refueling adapter according tothe prior art;

FIG. 2 is a partial side view of an aircraft that includes aninteroperable aerial refueling apparatus according to an embodiment ofthe invention;

FIG. 3 is an exploded and partial cutaway view of the interoperableaerial refueling apparatus of FIG. 2;

FIGS. 4 through 8 are partial side views of an aircraft that includesthe interoperable aerial refueling apparatus of FIG. 2 that will be usedto describe a method of refueling an aircraft according to anotherembodiment of the invention; and

FIG. 9 is a side elevation view of an aircraft having one or more of thedisclosed embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to aerial refueling of aircraft, and inparticular to interoperable aerial refueling apparatus and methods. Manyspecific details of certain embodiments of the invention are set forthin the following description and in FIGS. 2 through 9 to provide athorough understanding of such embodiments. One skilled in the art,however, will understand that the present invention may have additionalembodiments, or that the present invention may be practiced withoutseveral of the details described in the following description.

FIG. 2 is a partial side view of an aircraft that includes aninteroperable aerial refueling apparatus 30 according to an embodimentof the invention. The apparatus 30 includes a fairing 32 that is fixedlycoupled to a rear portion 34 of the aircraft 36. The fairing 32demountably retains a hose and drogue assembly 38 while the aircraft 36is in flight, while permitting a refueling boom 20 to be operatedwithout interference, so that a receiving aircraft configured to receivefuel using the boom and receiver system may be refueled. Although therefueling boom 20 is shown in a stowed position, it is understood thatthe boom 20 is angled downwardly and away from the rear portion 34 ofthe aircraft 36 when a refueling operation is conducted. When it isdesired to refuel an aircraft configured with the probe and droguesystem, the refueling boom 20 engagably receives the hose and drogueassembly 38 and demounts the assembly 38 from the fairing 32. The boom20 may be lowered downwardly and away from the rear portion 34 with thehose and drogue assembly 38 attached. Accordingly, aircraft configuredfor the probe and drogue assembly may then be refueled.

FIG. 3 is an exploded and partial cutaway view of the interoperableaerial refueling apparatus 30 of FIG. 2 that will be used to describethe apparatus 30 in greater detail. The hose and drogue assembly 38includes a receptacle 40 that is configured to receive a valve portion42 (boom refueling nozzle) of the telescoping extension portion 18 sothat the receptacle 40 is sealably retained by the valve portion 42. Forclarity of illustration, the telescoping extension portion 18 is shownin a partially extended position. It is understood, however, that thetelescoping extension portion 18 is typically fully retracted within theboom 20 while the boom 20 is in the stowed position, and correspondinglymay be fully extended when the boom 20 is deployed. The receptacle 40further includes an electrical contact 43 operable to verify that thereceptacle 40 is sealably and lockably coupled to the valve portion 42.When the valve portion 42 is opened, fuel may be communicated from theboom 20 to a drogue 44 that is positioned on a terminal end of theassembly 38. Verification of the coupling between the valve portion 42and the receptacle 40 may also be used to energize pumps located in anon-board fuel supply system within the aircraft 36.

With continued reference to FIG. 3, the apparatus 30 further includes aretainer 46 disposed within the fairing 32 that is configured to receivethe receptacle 40 within a recess 41 to retain the receptacle 40 whennot engaged by the valve portion 42. Accordingly, the retainer 46includes an internal structure within the recess 41 to lockably retainthe receptacle 40 within the retainer 46 so that the hose and drogueassembly 38 cannot detach from the aircraft 36 (as shown in FIG. 2)unless the receptacle 40 is properly positioned on the valve portion 42.Accordingly, the retainer 46 may also include an electrical switchpositioned within the recess 41 that is operable to provide anindication to one or more flight crewmembers that the receptacle 40 issuitably locked within the recess 41.

With reference now to FIGS. 2 and 3, the apparatus 30 may beincorporated into the structure of the aircraft 36 during themanufacture of the aircraft 36. Alternately, and in another specificembodiment of the invention, the apparatus 30 may be provided as aretrofit package for tanker aircraft that are configured with the boomand receiver system 20. The installation of the package thus enablestanker aircraft that are configured with the boom and receiver system 20to be used to refuel aircraft configured for the probe and droguesystem.

FIGS. 4 through 8 are partial side views of an aircraft that includesthe interoperable aerial refueling apparatus 30 of FIG. 2 that will beused to describe a method of aerial refueling according to anotherembodiment of the invention. FIG. 4 shows the aircraft 36 in flight andprior to a refueling operation. Accordingly, the boom 20 is in thestowed position, and the hose and drogue assembly 38 is secured withinthe retainer 46 (as shown in FIG. 3). As shown in FIG. 5, when it isdesired to refuel an aircraft configured with the probe and droguesystem, the telescoping extension portion 18 of the boom 20 extendsoutwardly from the boom 20 to engage the valve portion 42 of theextension portion 18 (as shown in FIG. 3) with the receptacle 40 of theassembly 38. When the valve portion 42 and the receptacle 40 aresuitably engaged, the receptacle 40 is released from the recess 41 inthe retainer 46 (as shown in FIG. 3). In addition, the extension portion18 may retract slightly to remove the receptacle 40 from the retainer46. The boom 20 may then be moved downwardly from the aircraft 36 to alowered position to refuel a receiving aircraft, and the fuel pumpsturned on to permit fuel to be communicated to the drogue 44.

FIG. 6 shows the refueling boom 20 in the lowered position with the hoseand drogue assembly 38 attached to the extension portion 18, which isshown in a fully extended position. The aircraft 36 is now ready torefuel a receiving aircraft that uses the probe and drogue system.Accordingly, the probe of the receiving aircraft is maneuvered intocontact with a valve positioned within the drogue 44, and fuel isdispensed. At the completion of the refueling operation, the receivingaircraft disengages the probe from the drogue 44, and departs. Thetelescoping extension portion 18 of the refueling boom 20 may then beretracted, and the boom 20 moved upwardly towards the stowed position,as shown in FIG. 7. When the boom 20 is fully in the stowed position,the extension portion 18 moves the receptacle 40 of the hose and drogueassembly 38 into the recess 41 of the retainer 46 (as shown in FIG. 3)and the receptacle 40 is locked into the recess 41. When the receptacle40 is properly locked, an indication is provided through the electricalcontact 43 located within the recess 41, and the valve portion 42 isdisengaged from the receptacle 40.

FIG. 8 shows the refueling boom 20 again in the lowered position, andwith the telescoping extension portion 18 fully extended from the boom20, so that the aircraft 36 may refuel a receiving aircraft configuredfor the boom and receiver system. During the refueling operation, thehose and drogue assembly 38 is securely locked within the fairing 32 bythe retainer 46 (as shown in FIG. 3) so that the assembly 38 will notinterfere with the refueling operation.

It will be appreciated that a variety of alternate embodiments of theinvention may be conceived, and that the invention is not limited to theparticular embodiments described above and shown in FIGS. 2–8. Forexample, in alternate embodiments, alternate ways of connecting the endof the refueling boom 20 to the hose and drogue assembly 38 may beconceived. More specifically, in alternate embodiments, the end of theboom 20 need not be inserted into the receptacle 40 of the hose anddrogue assembly 38, but rather, may encapsulate a tip portion of thehose and drogue assembly 38. In further embodiments, other ways ofcoupling the end of the boom 20 to the hose and drogue assembly 38 maybe conceived.

Similarly, a variety of alternate ways of releasably coupling the hoseand drogue assembly 38 to the fairing 32 or other portion of theinteroperable aerial refueling apparatus 30, or to the aircraft 36, maybe conceived. For example, the retainer 46 having the recess 41 may bereplaced with any other suitable securing device, including but notlimited to a mechanical retaining clip, an electromechanical retainingdevice, or an electromagnetic retaining device. Such other suitablesecuring devices need not engage with the receptacle 40, but rather, maysecurely engage with any other suitable portion of the hose and drogueassembly 38, including, for example, the hose portion of the assembly38.

Those skilled in the art will also readily recognize that the foregoingembodiments may be incorporated into a wide variety of differentsystems. Referring now in particular to FIG. 9, a side elevation view ofan aircraft 300 having one or more of the disclosed embodiments of thepresent invention is shown. With the exception of the embodimentsaccording to the present invention, the aircraft 300 includes componentsand subsystems generally known in the pertinent art, and in the interestof brevity, will not be described in detail. As shown in FIG. 9, theaircraft 300 generally includes one or more propulsion units 302 thatare coupled to wing assemblies 304, or alternately, to a fuselage 306 oreven other portions of the aircraft 300. Additionally, the aircraft 300also includes a tail assembly 301 and a landing assembly 310 coupled tothe fuselage 306. The aircraft 300 further includes other systems andsubsystems generally required for the proper operation of the aircraft300. For example, the aircraft 300 includes a flight control system 312(not shown in FIG. 9), as well as a plurality of other electrical,mechanical and electromechanical systems that cooperatively perform avariety of tasks necessary for the operation of the aircraft 300.Accordingly, the aircraft 300 is generally representative of a tankeraircraft, which may include, for example, the KC-10 and KC-135 aircraftproduced by The Boeing Company of Chicago, Ill. Although the aircraft300 shown in FIG. 9 generally shows a tanker aircraft, it is understoodthat the various embodiments of the present invention may also beincorporated into flight vehicles of other types. Examples of suchflight vehicles may include rotary wing aircraft, as illustrated morefully in various descriptive volumes, such as Jane's All The World'sAircraft, available from Jane's Information Group, Ltd. of Coulsdon,Surrey, UK.

With reference still to FIG. 9, the aircraft 300 may include one or moreof the embodiments of the interoperable aerial refueling apparatus 314according to the present invention, which may operate in associationwith the various systems and sub-systems of the aircraft 300, aspreviously described.

While preferred and alternate embodiments of the invention have beenillustrated and described, as noted above, many changes can be madewithout departing from the spirit and scope of the invention.Accordingly, the scope of the invention is not limited by the disclosureof these preferred and alternate embodiments. Instead, the inventionshould be determined entirely by reference to the claims that follow.

1. An aerospace vehicle, comprising: a fuselage; a refueling boomoperatively coupled to the fuselage and having a terminal end; anempennage operatively coupled to the fuselage; and an interoperablerefueling apparatus coupled to the empennage, the apparatus furthercomprising: a receptacle fluidly coupled to a refueling drogue, thereceptacle being configured to fluidly receive the terminal end of therefueling boom; and a retainer coupled to the vehicle that is configuredto removably retain at least the receptacle when the vehicle isrefueling an aircraft configured to directly engage the terminal end ofthe boom, and to release the receptacle when the terminal end of therefueling boom engages the receptacle so that an aircraft configured toreceive the refueling drogue may be refueled.
 2. The vehicle of claim 1,wherein the terminal end further comprises a valve.
 3. The vehicle ofclaim 2, wherein the receptacle further comprises an electrical contactoperable to couple an electrical signal between the receptacle and theterminal portion of the boom, the electrical signal being operable to atleast command the valve to an open position.
 4. The vehicle of claim 1,wherein the receptacle further comprises a locking mechanism thatlockably retains the receptacle oil the terminal end when the receptacleand the terminal end are engaged.
 5. The vehicle of claim 1, furthercomprising a fairing coupled to the vehicle that supports the retainer.6. The vehicle of claim 1, wherein the retainer further comprises arecess configured to receive the receptacle.
 7. The vehicle of claim 1,wherein the retainer further comprises a locking mechanism that lockablyretains the receptacle when the vehicle is refueling an aircraftconfigured to directly engage the terminal end of the boom.
 8. Thevehicle of claim 1, wherein the retainer further comprises an electricalswitch that provides an indication to at least a flight crew of thevehicle that the receptacle is suitably captured by the retainer.
 9. Thevehicle of claim 1, further comprising a length of flexible hoseextending between the receptacle and the drogue.